NodeRed + HA + MQTT 一条链路看温度：从传感器到电子钟显示

┌─────────────┐    ┌──────────────┐    ┌──────────┐    ┌──────────┐    ┌──────────────┐
│ 温度传感器   │ ──→ │ Xiaomi 网关  │ ──→ │ HA 状态  │ ──→ │ NodeRed  │ ──→ │ MQTT Broker  │
│ (Zigbee)    │    │ (网关 IP)     │    │ REST API │    │ (处理流) │    │ (1883)     │
└─────────────┘    └──────────────┘    └──────────┘    └──────────┘    └──────┬───────┘
                                                                              │
                                                                              ▼
                                                                      ┌──────────────┐
                                                                      │ ESP-D1 电子钟 │
                                                                      │ (墨水屏)     │
                                                                      └──────────────┘

# 通过 HA REST API 查看客厅温度
curl -s -H "Authorization: Bearer $HA_TOKEN" \
  "http://your-ha-server:8123/api/states/sensor.miaomiaoc_cn_blt_3_19p32ttas5g00_t2_temperature_p_2_1"

# 返回示例
{
  "entity_id": "sensor.miaomiaoc_cn_blt_3_19p32ttas5g00_t2_temperature_p_2_1",
  "state": "28.3",
  "attributes": {
    "unit_of_measurement": "°C",
    "device_class": "temperature",
    "friendly_name": "客厅温湿度计 温度湿度传感器 温度"
  },
  "last_updated": "2026-08-25T15:54:13.093593+00:00"
}

# Docker 方式部署
docker run -d \
  --name NodeRed \
  --restart unless-stopped \
  -p 1880:1880 \
  -v /path/to/nodered/data:/data \
  nodered/node-red

# 安装 HA 节点包
# 进入容器
docker exec -it NodeRed /bin/bash
# 在容器内安装
cd /data
npm install node-red-contrib-home-assistant-websocket

[server-state-changed] → [function] → [mqtt out] → [ESP-D1]

{
  "entity_id": "sensor.miaomiaoc_cn_blt_3_19p32ttas5g00_t2_temperature_p_2_1",
  "new_state": {
    "state": "28.3",
    "attributes": {
      "unit_of_measurement": "°C",
      "friendly_name": "客厅温湿度计 温度"
    }
  },
  "event": "state_changed"
}

// 识别是哪个传感器
var entity_id = msg.payload.entity_id;
var temp = parseFloat(msg.payload.new_state.state);

// 跳过非温度事件
if (isNaN(temp)) return null;

// 根据 entity_id 判断设备位置
var location = "未知";
if (entity_id.includes("19p32ttas5g00")) location = "客厅";
else if (entity_id.includes("1fra6pbmgkc00")) location = "主卧";

// 构造 ESP-D1 需要的显示格式
msg.payload = {
  time_logo_id: 6,
  time_logo_show: true,
  display_text: location + " " + temp.toFixed(1) + "°C"
};

return msg;

# 订阅主题，检查消息是否到达
mosquitto_sub -h your-mqtt-server -p 1883 -t "esp-d1/display_json"

# 收到消息示例
{"time_logo_id": 6, "time_logo_show": true, "display_text": "客厅 28.3°C"}

// Arduino 伪代码
void callback(char* topic, byte* payload, unsigned int length) {
  String json = String((char*)payload).substring(0, length);

  // 解析 JSON
  int logoId = getJsonValue(json, "time_logo_id");
  bool showLogo = getJsonValue(json, "time_logo_show");
  String displayText = getJsonValue(json, "display_text");

  // 更新墨水屏
  epaper.clear();
  if (showLogo) drawLogo(logoId);
  drawText(displayText, 20, 60);
  epaper.display();
}

# Step 1: 查 HA 状态
curl -s -H "Authorization: Bearer $HA_TOKEN" \
  "http://your-ha-server:8123/api/states/sensor.miaomiaoc_cn_blt_3_19p32ttas5g00_t2_temperature_p_2_1" \
  | jq '.state'

# Step 2: 查 NodeRed 流（通过 HA 事件触发，自动处理）
# 查看 NodeRed 日志
docker logs NodeRed --tail 20

# Step 3: 查 MQTT 消息
mosquitto_sub -h your-mqtt-server -p 1883 -t "esp-d1/display_json" -C 1

# Step 4: 看屏幕 —— 物理观察